Waterproofing composition and articles treated therewith



Patented an, 14, 1932 UNITED STATES PATENT OFFICE CHARLES E. BURKE AND WALTER E. LAWSON, OF WILMINGTON, DELAWARE, ASSIGNORS TO E. I. DU PONT DE NEMOURS 8; COMPANY, OF WILMINGTON, DELAWARE, A COR- roaamon or DELAWARE warnnrnoormo comrosn'ron AND ARTICLES ram-ran rnnanwrrn no Drawing. Application filed July 9,

, of being waterproof and sufliciently rigid to hold their shape and at the same time preserve their elasticity.

It is therefore an object of this invention to improve the waterproofing of paper and articles treated therewith.

It is another object of this invention to produce a stiffer and more uniform shell, so

that better patterns are secured and more uniform velocity is obtained, and to produce a shell having an improved appearance.

It is a further object of this invention to improve the waterproofing and stiffening of a s otgun shell without unduly sacrificing its elasticity;

It is also an object of this invention to make shells more resistant to abrasion, which is caused by the long continued tumbling often encountered when shells are carried loose in V a hunting jacket, so they will retain their i rapidly) by heating to form a har close shooting qualities.

-We have found that these objects can be accomplished by treating paper or articles made therefrom, such as shotgun shells, with solutions containing a polymerizable substituted ethylene. An example of such a polymerizable substituted ethylene is styrene whlch can be dissolved in a suitable solvent (with or without a softener, and with or without coloring matter), applied to the shell, and polymerized by standing, or (more resistant,

and waterproof surface.

We have found that these objects can be 1928. Serial No. 291,480.

Ewample 1 Parts by weight Meta styrene 18 Tricresyl phosphate i 3. 6

Solvent-Ethyl acetate 20; butyl acetate 30; toluene 30; xylene 20 100 l Used as a spraying lacquer over paraflin impregnated shells, one coat increased the time limit for total immersion in water without swelling or opening of crimp from two hours to seven hours. Used as a dipping lacquer, two coats increased the time limit to eight hours.

Example 2 Parts by a weight Vinyl chloride, alpha polymer 18 This composition gave results similar to those in Example 1.

Example 3 Parts by weight Polymerized' vinyl chloroacetate; 25

Solvent-Ethyl acetate 40; butyl acetate 35; acetone 15; cellosolve acetate 10-- 100 shells to from five to five and one-half hours for the treated shells. a

' spraying or Ewam le 4 p Parts by weight Vinyl chloride, acetone soluble polymer. 11

Polymerized vinyl acetate 11 Solvent-Acetone 20; ethyl acetate 20;

butyl acetate30; chlorobenzene 30...." 100 Used as a dipping lacquer, two coats increased the time limit to seven hours.

Example 5 Parts by weight Vinyl chloride-vinyl acetate polymer--- 37 Solvent-acetone 25; ethyl acetate 25;

butyl acetate 20; toluene 30 100 This mixture, being of greater viscosity than any of the preceding lac uers, gave exceptionally high protection. hotgunshells were protected for 20 to 24 hours and even longer without any change in their appearance.

Although the examples given are limited to meta styrene and vinyl esters, compositions are useful for this purpose, such as polymers of other vinyl esters, especially the esters of higher fatty acids and polymerized vinyl ethers; polymers of allylene compounds; 'homologues of meta styrene, such as polymers of ethyl styrene and paramethyl styrene; and polymers of other highly unsaturated hydrocarbons.

We have found it desirable to modify meta styreneand its homologues, such as meta proofing composition containing many other solvent for paraflin such as benzene or gasoline, or to subject them to a moderate bufiing treatment.

Although we have stressed herein the use of our coating composition for waterproofing shotgun shells, it is equall useful for waterproofing or moisture-proo g paper for other purposes.

As many apparently widely different embodiments of this invention maybe made without departing from the spirit thereof, it is to be understood that we do not limit ourselves to the foregoing examples or description, except as indicated in the following patent claims.

We claim:

1. A shotgun shell treated with a composition containing meta styrene.

2. A shotgun shell coated with a composition containing meta styrene.

3. A shotgun shell coated with a waterabout 18 by weight of meta styrene, about 3.6 parts by weight of tricresyl phosphate, and about 100 parts by weight of solvent.

In testimony whereof we afiix our signatures.

CHARLES E. BURKE. WALTER E. LAWSON.

parts paramethyl styrene and other substitution products, to soften them and render them less brittle, suitable softeners including dibutyl phthalate, tricresyl phosphate and butyl stearate.

We have also found it desirable to modify polymerized vinyl chloride, by treatin with suitable softeners, such as dibutyl phtialate or glyceryl dibenzyl ether, by mixing with drying oils, such as China wood, linseed, and perilla oils, or by adding other compatible vinyl derivatives, such as vinyl acetate.

These compounds may be incorporated in dipping lacquers and used as coating compositions on loaded shells, or may be employed for the impregnation of shells previous to loading. If desired, the impregnated shells, previous to loading, may be subjected to a baking process to increase their water resistance. For example, the water resistance of shells treated with polymerized vinyl chloracetate is markedly increased by baking at 65 C. for two hours, or at higher temperatures for correspondingly shorter periods of time. If the loaded shells are of the ordinary paraflin impregnated type, it is usually advisable to wash the shells with-a 

